/Engine/Source/Runtime/GeometryFramework/Public/Components/DynamicMeshComponent.h
If bEnabled=true, sets bEnableComplexCollision=true and CollisionType=CTF_UseComplexAsSimple If bEnabled=true, sets bEnableComplexCollision=false and CollisionType=CTF_UseDefault
void SetComplexAsSimpleCollisionEnabled ( bool bEnabled, bool bImmediateUpdate )